title: Effect of environmental stress factors on ecophysiological traits and susceptibility to pathogens of five Populus clones throughout the growing season.
abstract: The variability of ecophysiological traits associated with productivity (e.g., water relations, leaf structure, photosynthesis and nitrogen (N) content) and susceptibility to fungal and insect infection were investigated in five poplar clones (Populus deltoides Batr.-Lux clone; Populus nigra L.-58-861 clone and Populus × canadensis Mönch.-Luisa Avanzo, I-214 and Adige clones) during their growing season. The objective of the study was to determine their physiological responses under summer constraints (characteristic of the Mediterranean climate) and to propose clone candidates for environmental restoration activities such as phytoremediation. Relative water content, the radiometric water index and (13)C isotope discrimination (Δ(13)C) results reflected improved water relations in Adige and Lux during summer drought. Leaf structural parameters such as leaf area, leaf mass per area, density (D) and thickness (T) indicated poorer structural adaptations to summer drought in clone 58-861. Nitrogen content and Δ(13)C results pointed to a stomatal component as the main limitant of photosynthesis in all clones. Adige and Lux showed enhanced photoprotection as indicated by the size and the de-epoxidation index of the xanthophyll-cycle pool, and also improved antioxidant defence displayed by higher ascorbate, reduced glutathione, total phenolics and α-tocopherol levels. Photoprotective and antioxidative responses allowed all clones to maintain a high maximum quantum yield of PSII (Fv/Fm) with the exception of Luisa Avanzo and 58-861 which experienced slight photoinhibition in late spring. The study of susceptibility to rust (Melampsora sp.) and lace bug (Monosteira unicostata Muls. and Rey) infections showed Adige and Lux to be the most tolerant. Overall, these two clones presented high adaptability to summer conditions and improved resistance to abiotic and biotic stress, thereby making them highly commendable clones for use in environmental remediation programmes.
authors.affiliation: Facultat de Biologia, Unitat de Fisiologia Vegetal, Departament de Biologia Vegetal, Universitat de Barcelona, Diagonal 643, E-08028 Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Fernàndez-Martínez
authors.forename: Massimo
authors.initials: M
authors.lastname: Zacchini
authors.forename: Georgina
authors.initials: G
authors.lastname: Elena
authors.forename: Beatriz
authors.initials: B
authors.lastname: Fernández-Marín
authors.forename: Isabel
authors.initials: I
authors.lastname: Fleck
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001487:Basidiomycota; D002980:Climate; D060467:Disease Resistance / Q000235:genetics*; D055864:Droughts; D007313:Insecta; D019083:Mediterranean Region; D010788:Photosynthesis / Q000235:genetics*; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D032107:Populus / Q000235:genetics* / Q000502:physiology; D012621:Seasons; D013045:Species Specificity; D013312:Stress, Physiological / Q000235:genetics*; D024341:Xanthophylls / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D045332:Photosystem II Protein Complex; D024341:Xanthophylls
keywords: biotic stress; chloroplast pigments; photochemistry; poplar; water stress; water use efficiency